EVANSTON, Ill. - A school district in Illinois has sparked controversy with its new dress code policy regarding leggings.

Students have started a petition and now a debate is raging around the question: how tight is too tight?

Yoga pants, leggings. Students at Haven Middle School in Evanston can wear these pants including skinny jeans, but they have to follow one rule.

"They're simply looking for girls to dress appropriately and make sure they're covered," said Melissa Burgia, spokesperson for Evansville/Skokie District 65.

The letter sent out by the Evanston school's principal says if the leggings are worn, a shirt, shorts or skirt worn over them must be fingertip length over the pants.

Reporter: "What prompted all this in the first place?"

"I think there was some concern over the consistency in enforcing the policy among students. Everybody should be dressed appropriately, in a professional manner to be in such a public setting," said Burgia.

Five students say they are among dozens opposed to the policy, so much so they've all signed a petition.

"We feel that the dress code is a violation of the First Amendment," said student Corbin Kimrey.

"People should have the ability to express themselves through whatever they want even clothing… anything," said student Abe Levinson.

Reporter: "As a mom what's your thought on the whole thing."

"I think kids should dress appropriately for school and for the most part, the kids do," said parent Lori Colbert.

The principal's advisory team says it will review the dress code next week, and will take input from students and parents.